Vertical I.C. Rupnow Engine

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Brian Rupnow

Design Engineer
Project of the Month Winner
Joined
May 23, 2008
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Location
Barrie, Ontario, Canada
Okay, I admit, I'm playing a bit here. I wanted to see how a vertical cylinder 1" bore x 1 1/4" stroke open crankcase engine would look. It looks good so far, but without a cylinder head and ignition points yet. Probably will go for an atmospheric intake valve.
 
I think I'm going to try something different this time, rather than using my old tried and true early Chrysler ignition points. I've seen a couple of builds now where people have used Tecumseh ignition points which can be operated by a pushrod, rather than having to ride directly on the ignition cam. I can see where that would open up a world of choice in terms of where the points could be positioned on the engine. If anybody knows the model number or part number for these Tecumseh points please let me know.
 
Brian,
Rather than go to the trouble of designing in a place for points why not simplify the whole thing with a Hall sensor. Small, clean and neat.
gbritnell
 
George--For me to buy all of the components from Roy Scholl or a similar supplier, ends up costing me about $100 for all of the components, batteries, switches, etcetera, when I go the magnet/hall effect sensor route. If I just buy points and condenser and a switch, it costs me about $20.00. I have my "coil in a box" that readily transfers from one engine to another, and a small wet cell 12 volt garden tractor battery that does the same. It's just a matter of economics.---Brian
 
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So, this design has got me through a rainy Canada day. Good wife was busy all day doing financial books for various and sundry poor folks (read "relatives") and didn't want to be bothered, so this was a fun way to spend a day. I still have valves and ignition to play away at, but I'll wait for another day to do that.
 
Looking great so far Brian. Very tempted to give it a try.
 
Brian - Here is a challenge for you - "Piston trip igniter". Battery, low tension coil and wire to insulated bolt in head is all you need.

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So there we have it!! What a neat little engine. The overall sizes haven't changed from the drawing that was posted earlier. This is a very simple engine, with a throttle style carburetor, no "hit and miss". I still have to sort out the ignition system, but this engine is about as simple as the Webster. I will post more as I get time, but it will go quickly. I'm interested--If I build this and post the drawings as .pdf files, who would be willing to build it? It would be a "build along with Brian" sort of thing.



 
Brian, what is to stop the crankshaft moving end to end and the crank or flywheel rubbing on the main frame casting. You have gaps at each end between the bearings and web/flywheel so shaft can move.

I would suggest a simple raised area on each of those parts that bears against the inner race of the bearings. Much like these.

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Thank you Jason--I will probably use a brass washer on each side to prevent end-play in the crankshaft, one between frame and flywheel, one between crank "web" and frame. Longboy--Thank you for the numbers. I've just blown up my mouse!!!:eek::eek:--Its been getting jumpier for about two weeks, with the pointer dashing off on side trips across the screen without my intervention.--So--I just sprayed the underside with eyeglass cleaner and scrubbed with a toothbrush, then wiped it dry. Now it doesn't work at all!!!---Damn!!! I've borrowed the mouse from my wife's laptop (she uses the built in track-ball anyways.) but it is a different size than my old mouse and feels really weird.
 
Brian, what is to stop the crankshaft moving end to end and the crank or flywheel rubbing on the main frame casting. You have gaps at each end between the bearings and web/flywheel so shaft can move.
I make Delrin spacers that ride the inner bearing races, filling up those gaps with a little thrust movement reserve on the crankshaft.
 
Longboy--I chased down the "Sentinel' engine thread, and you did a great job on it. Very fancy overhead cam set-up too. I'm aiming for "simple" in hopes of getting a few others to build along with me.---Brian
 
I bought a new "mouse" and got it up and running. That old mouse lasted about 12 or 13 years, so it doesn't owe me any money!! I really, really like the look of bronze for a flywheel, but Oh my god, it's expensive. I think I have enough of that big bronze weight that I salvaged from the landfill to make one more nice flywheel, but it's going to be a close thing. The piece I have left is 5 3/4" diameter x 1 3/4" long.-I may have to turn half of it into chips in the lathe, because there is no good way to hold it to saw it in half. All of my saws are too light anyways. I've been getting 7/8" lengths sawed off it at my local metal supplier with his giant self-feeding bandsaw, but the last time he cut a length off he said that he couldn't make any more cuts.
 
Count me in Brian. Looks like a nice easy project to see out the winter here in Oz.
 
Since I already have a couple of people who want to start on this project, here are a couple of parts to get you started that aren't going to change.

 
I'm keen to get back into the shop (and this looks like a perfect project) but I'm not sure how much time I will have. At this stage I think I'll remain quiet but maybe I'll make a few parts and see what happens.
 

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